Effects of hydrogen peroxide priming on yield, photosynthetic capacity and chlorophyll fluorescence of waterlogged summer maize

Extreme rainfall events during the summer maize growth and development periods, which have induced losses in summer maize production. There was a completely randomized block experiment being designed with four treatments: waterlogging for 6 days at the V3 stage (C-W), H(2)O(2)-priming + non-waterlogging (H-CK), H(2)O(2)-priming + waterlogging for 6 days at the V3 stage (H-W) and control (C-CK). This study investigated the effects of H(2)O(2) priming on yield and photosynthetic parameters of (Zea mays. L) summer maize hybrid DengHai605 (DH605) by measuring the leaf area index (LAI), soil and plant analyzer development (SPAD) value, stomatal morphology, gas exchange parameters, and chlorophyll fluorescence parameters. The results showed that the net photosynthetic rate (Pn) was decreased after waterlogging through the stomatal limitation of CO(2) supply and reduction of PSII photochemical efficiency, which led to the decrease in dry matter accumulation and grain yield. H(2)O(2) priming increased the number of opening stomas, the stomatal length, and width, thus increasing Ci by 12.1%, which enhanced the Pn by 37.5%. Additionally, H(2)O(2) priming could improve the energy of dark reaction carbohydrates by increasing the light energy absorption and utilization, alleviating the function of PSII reaction centers, protecting the PSII receptor and donor side, and the electron transport chain. The φEo, φPo, φRo, and Ψo of H-W were increased by 89.9%, 16.2%, 55.4%, and 63.9% respectively, and the φDo was decreased by 23.5%, compared with C-W. Therefore, H(2)O(2) priming significantly enhanced the PSII photochemical efficiency, and increased the CO(2) supply in dark reactions to promote carbon assimilation, alleviating the waterlogging-induced damage to maize plant growth and grain yield.